void main() {
  //准备购物车数据
  List carts = [
    {"count": 2, "price": 10.0, "selected": true},
    {"count": 1, "price": 30.0, "selected": false},
    {"count": 5, "price": 20.0, "selected": true}
  ];
  print(isSelectedALL(carts));
}

bool isSelectedALL(List carts) {
  //方式1：
  // return carts.every((item)=>item['selected']);

  //方式2： 假设法
  bool result = true;
  for (var item in carts) {
    if (!item['selected']) {
      result = false;
    }
  }
  return result;
}
